/*

 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.nashorn.internal.runtime;

import static jdk.nashorn.internal.parser.TokenType.EOF;

import jdk.nashorn.internal.parser.Lexer;

import jdk.nashorn.internal.parser.Token;

import jdk.nashorn.internal.parser.TokenStream;

import jdk.nashorn.internal.parser.TokenType;

/**

 * Utilities for debugging Nashorn.

 *

 */

public final class Debug {

    private Debug() {

    }

    /**

     * Return the topmost JavaScript frame in a stack trace

     * @return line describing the topmost JavaScript frame

     */

                return ste.toString();

            }

        }

        return "<native code>";

    }

    /**

     * Return the topmost JavaScript frame from the current

     * continuation

     * @return line describing the topmost JavaScript frame

     */

    public static String firstJSFrame() {

        return firstJSFrame(new Throwable());

    }

    /**

     * Return the system identity hashcode for an object as a human readable

     * string

     *

     * @param x object

     * @return system identity hashcode as string

     */

    public static String id(final Object x) {

        return String.format("0x%08x", System.identityHashCode(x));

    }

    /**

     * Same as {@link Debug#id} but returns the identity hashcode as

     * an integer

     *

     * @param x object

     * @return system identity hashcode

     */

    public static int intId(final Object x) {

        return System.identityHashCode(x);

    }

    /**

     * Return a stack trace element description at a depth from where we are not

     *

     * @param depth depth

     * @return stack trace element as string

     */

    public static String stackTraceElementAt(final int depth) {

        return new Throwable().getStackTrace()[depth + 1].toString(); // add 1 to compensate for this method

    }

    /**

     * Determine caller for tracing purposes.

     * @param depth depth to trace

     * @param count max depth

     * @param ignores elements to ignore in stack trace

     * @return caller

     */

    public static String caller(final int depth, final int count, final String... ignores) {

        String result = "";

        final StackTraceElement[] callers = Thread.currentThread().getStackTrace();

        int c = count;

loop:

        for (int i = depth + 1; i < callers.length && c != 0; i++) {

            final StackTraceElement element = callers[i];

            final String method = element.getMethodName();

            for (final String ignore : ignores) {

                if (method.compareTo(ignore) == 0) {

                    continue loop;

                }

            }

            result += (method + ":" + element.getLineNumber() +

                       "                              ").substring(0, 30);

            c--;

        }

        return result.isEmpty() ? "<no caller>" : result;

    }

    /**

     * Dump a token stream to stdout

     *

     * TODO: most other bugging goes to stderr, change?

     *

     * @param source the source

     * @param lexer  the lexer

     * @param stream the stream to dump

     */

    public static void dumpTokens(final Source source, final Lexer lexer, final TokenStream stream) {

        TokenType type;

        int k = 0;

        do {

            while (k > stream.last()) {

                // Get more tokens.

                lexer.lexify();

            }

            final long token = stream.get(k);

            type = Token.descType(token);

            System.out.println("" + k + ": " + Token.toString(source, token, true));

            k++;

        } while(type != EOF);

    }

}